From a first aspect, the present invention relates to a method of curing a binder. The invention also embraces a binder composition, a foundry composition comprising a binder and a foundry aggregate and a consignment of compositions for use in the foundry composition. The invention relates primarily to binders suitable for use in a foundry for binding together particles of a foundry aggregate to form a core or a mould.
In GB No. 2,112,003A, there is disclosed a method of preparing a foundry core wherein there is mixed with a foundry aggregate calcium hydroxide and an aqueous solution of sodium polyacrylate, the mixture is formed to the required shape and carbon dioxide is passed through the mixture to cure the binder. However, use of carbon dioxide as the curing agent is not entirely satisfactory, in all circumstances. For example, it is inconvenient to cure by gasing with carbon dioxide single cores or small numbers of cores, when there is no long production run. It is also unsatisfactory to cure by gasing with carbon dioxide some large cores and moulds.